The present invention disclosed herein relates to a solar cell module and a method of manufacturing the same, and more particularly, to a solar cell module including a transparent electrode layer and a method of manufacturing the same.
A Copper Indium Gallium Selenide (CIGS) thin film solar cell, which attracts a lat of attention recently, has higher efficiency than an amorphous silicon solar cell and relatively high stability such as no initial degradation. Thus, the CIGS thin film solar cell is now in development for commercialization. Additionally, the CIGS thin film solar cell has properties as excellent as a lightweight high-efficient solar cell for space, which could replace a typical single crystal silicon solar cell, is studied first. That is, its power generation amount per unit weight is about 100 W/kg, which is far more excellent than about 20 W/kg to about 40 W/kg of a typical silicon or GaAs solar cell. Since its power generation amount reaches about 20.3% in a current single junction structure, the CIGS thin film solar cell has an almost equal maximum high efficiency to a typical single crystal silicon solar cell.
Despite those advantages, the CIGS thin film solar cell has low productivity. The reason is that since the CIGS thin film solar cell module is completely manufactured typically after undergoing various stages of a vacuum process, manufacturing costs are high due to large investment on equipment and mass productivity is low. The CIGS thin film solar cell module includes a bottom electrode, a light absorbing layer, and a window electrode layer, all of which are stacked on a substrate. The window electrode layer may include a transparent electrode layer having a thickness of several μm to tens of μm. The window electrode layer may be formed through a physical vapor deposition method or a chemical vapor deposition method.
However, due to a low step coverage of the window electrode layer, the physical vapor deposition method may cause electrical contact defects at a sidewall of a trench that separates light absorbing layers. As a result, its production yield is decreased. When a window electrode layer is formed with a thickness of more than about 3 μm in order to resolve such an issue, the time consumed for a deposition process becomes longer and the amount of targets consumed is increased. Therefore, its productivity is decreased. Furthermore, since the window electrode layer formed through the chemical vapor deposition method may contain a large amount of impurities, its electrical conductivity is low. Therefore, the window electrode layer is required to be formed with a thickness of more than about 3 μm through the chemical vapor deposition method. Accordingly, when a typical method for manufacturing a window electrode of a solar cell module is used, a physical deposition or chemical deposition method may reduce its yield and productivity.